The RNLI yesterday apologised for the crude film, which also features homophobic slurs and jokes about violence against women.

The 18-strong team videoed themselves wearing the charity's distinctive red and yellow uniforms in the lifeguard station on Sandanks beach, Poole, Dorset.

They also used RNLI-branded props as part of the show, which was uploaded to YouTube.

An RNLI spokesman issued an unreserved apology and warned that they would be taking disciplinary action.

Spencer Gammond, head of communications at the charity, said: "We are extremely dismayed by the offensive content of this video and apologise unreservedly to anyone who has seen it.

"We are carrying out a thorough investigation and will take disciplinary action against those who have used RNLI resources inappropriately and shown such disregard for the public, our supporters and our charity's good name.

"We hope people will understand this instance of shameful behaviour by a very small minority is not representative of our 900 lifeguards.

"We will take firm steps to prevent a recurrence."

The film, entitled LGTV, is set around the beaches in Poole and uses RNLI-branded buildings, cars, windbreaks, surf boards and umbrellas.

It opens with the Baywatch theme tune before zooming in to an animated television, with a series of imaginary channels on the screen.

The film then appears to select a channel at a time, beginning with 'Animal Planet', with real-life lifeguards mimicking dolphins, salmon, bears, lions, monkeys and meerkats

In a "You've Been Framed" section, a male lifeguard is caught on camera with his shorts pulled down, simulating sexual intercourse with a red buoyancy aid.

The film ends with three near-naked men, dressed only in red Speedos, attempting to recreate Beyonce's 'Single Ladies' dance, under the heading "Beyondgay".

In a nod to Hollywood comedy Anchorman, the film signs off: "Stay classy Poole Bay."

The RNLI said it had contacted YouTube and the person who uploaded the video in a bid to get it removed.